Offline Basemap Solution for Mobile Mapping in Android or Apple IOS Devices.

Hi, this post is about four solutions about how to perform offline basemap creation for mobile mapping in Android or Apple IOS devices. For this first part. I will demonstrate about GeoPDF format that is widely supported in most GIS Software. I will demonstrate how to write GeoPDF in ArcGIS Desktop (ArcGIS Pro also has this functionality) and QGIS, followed by how to load the GeoPDF Map in a supported Android/IOS App. Unfortunately, when this video is made, the only app that can read GeoPDF is only Avenza PDF Maps (available in Android and IOS). The rest is no longer updated (TerraGO GeoPDF) or part of paid services (Global Mapper Mobile Pro).

Utilizing GeoPDF for field mapping basemap is very effective and simple. All data in one file. They are structured and tailored according to your setting on the GIS Desktop. They also provide good loading performance as long as the file is not relatively huge.

For the second part. I will demonstrate the ArcGIS Mobile Map Package (MMPK) format, which is, unfortunately, only supported in the ArcGIS software family. I will demonstrate how to write the MMPK in ArcGIS Pro, followed by how to load the MMPK into the ArcGIS Field Maps available on Android and iOS. MMPK can be treated as a complete mobile mapping data package. It supports various types of vector and raster layers in ArcGIS Native format (shapefiles, rasters, geodatabases, network datasets, locators, and even the ability to reference Map and Feature Services in the mobile app). If you store the vector layer in MMPK, you will retain all the attributes (or not, up to you). This implementation is quite different from other types of offline data packaging, such as Vector Tile. MMPK also has an expiration feature. So, when the expiration date is passed, the map is no longer possible to open in any mobile app. MMPK loading in ArcGIS mobile app (such as ArcGIS Field Maps or ArcGIS Navigator) can also be done anonymously. However, this anonymous access is only available if you publish the MMPK using the ArcGIS Publisher Extension for ArcGIS Pro (sold separately from the main ArcGIS Pro License).

For this third part. I will demonstrate the MBTiles format. MBTiles is one example of an open format, so, many software and libraries can write MBTiles (Global Mapper, MOBAC, QGIS, GDAL, Mappertive, Mapbox Studio, and many more). MBTiles can host both raster and vector tiles, and currently, there are few apps on Android and iOS that can read them (either free or paid apps). In this video, I will demonstrate how to generate MBTiles from a raster file (which can be combined with vectors too if you want) using GDAL, and then I will demonstrate how to read the MBTiles in the LOCUS GIS Mapping App available in the Android Google Play Store. MBTiles is a packed image or vector graphics tile and structured by zoom levels just like other tile mapping standards, so, compared with GeoPDF or KML/KMZ, MBTiles is more dynamic in cartographic visualization. You can set layer symbolization or label treatments at every zoom level differently. This is something you can't do with GeoPDF or KML, although GeoPDF or KML are simpler in terms of file creation. Because it follows a tiling scheme, MBTiles file size can be huge, even for small areas. For this matter, file-based maps like GeoPDF or KML/KMZ are more efficient. All in all, there is no perfection in choosing GIS technology for your application. There are always pros and cons. Your requirements and goals should always be your guide to achieving a successful application.

For the fourth part. I will demonstrate the KMZ SuperOverlay format. KMZ SuperOverlay is like normal KML/KMZ, however, it is dedicated to storing raster data (tiled), so the raster data can be opened in native KML/KMZ software such as Google Earth Pro, and still retain the georeference information.

Because KML/KMZ is quite popular compared to other file-based tiled geospatial data formats (such as MBTiles), many GIS and mapping software programs can read it, including some of the best-known mobile mapping apps on Android or iOS. KMZ SuperOverlay is also easier to make compared to others (MBTILES, PMTILES, ArcGIS MMPK, Geopackage), you don't have to specify the planned zoom level. Just load and convert, and you will get the result. So, KMZ SuperOverlay is kind of combining the benefits of GeoPDF and MBTiles for offline basemap serving.  In this video, I will demonstrate how to build a KMZ SuperOverlay using GDAL and Global Mapper, followed by how to open the data in the Android Mapping App. One thing I should tell you, currently, because implementation of KMZ Superoverlay are different in every software (although they are all compatible in Google Earth Pro), only KMZ superoverlay generated in Global Mapper that can be read in Mobile Mapping App such as Locus GIS. This situation might be different in future due to constant software development, so, always check and test before doing the data conversion.